70 CORUNDUM IN THE UNITED STATES. [bull. 180. 
often in a series of pockets that are frequently connected with each 
other along the strike by a thin streak of chlorite and have a general 
dip in the vein of about N". 30°. In the direction of the dip, however, 
the emery is more or less continuous. The width of the vein varies 
from a few feet to 10 or 12, with an average width for the emery of 
about 6 feet. This is the most extensive deposit of emery known in 
this country. 
Emery has also been discovered in the vicinity of Huntington, Mass., 
but no development work has as yet been done. 
NEW YORK. 
The emery deposits of this State occur associated with the norite 
rocks in Westchester County that have been described on page 26. 
Deposits of magnetite and emery have been found at a number of 
places 3 to 4 miles southeast of Peekskill. These deposits vary 
considerably in character, some being a nearly pure magnetite, others 
containing magnetite and spinel, and still others magnetite, spinel, 
and corundum. Those within a mile north and northeast of Crugers 
Station have been worked for iron ore, while those worked for emery 
are in the southeastern part of Cortland Township. The principal 
openings have been made on a ridge running north from Colabaugh 
Pond and it is here that the ore has been mined. While the iron ore 
and emery appear to be very rich it was found upon examination that 
there was more or less of a dark-green mineral mixed with magnetite, 
and this mineral was shown by Williams l to be the pleonaste variety 
of spinel. There is also considerable spinel in the emery, and even 
when this is quite abundant it can not be distinguished in the hand 
specimens from that in which there is almost none of this mineral. 
At the emery deposits in the southeastern part of Cortland Town- 
ship the percentage of corundum varies considerably at different 
openings, and it is sometimes observed in small blue, white, and color- 
less crystals. Associated with most of the corundum there is spinel, 
and considerable of the ore that has been mined for emery has con- 
tained little or no corundum and has been made up of magnetite 
and spinel. An ore of this sort would have most of the requisite 
properties of a true emeiy except the high degree of hardness due to 
the corundum; and when made up into a wheel it would not have 
the cutting efficiency of a true emery wheel. The spinel, which is 8 
in hardness (corundum being 9), would pmy the same part in this ore 
as corundum in the true emery, and while not so hard as corundum 
it has the cutting qualities which would give the ore considerable 
value as an abrasive. For many purposes wheels made from this 
could be used fully as well as emeiy or corundum wheels and for 
some purposes they might be used to better advantage. The spinel 
would not interfere at all in the manufacture of a vitrified wheel. 
i Am. Jour. Sci., 3d series, Vol. XXXIII, 1882, p. 194. 
